Using Cartograms in Disease Mapping

Cartograms are known for their ability to effectively map socio-economic data through distorting geographies, while it is generally assumed that conventional maps are the best way of showing geographical information correctly. However, cartograms are seldom adopted to map disease. Recent years have seen the development of several new forms of cartogram, but there are no clear signs as yet to suggest that they will become prominent in disease mapping. The principal purpose of this study is to examine the reasons why cartograms have not been widely utilised for disease mapping and to also explore feasible ways of encouraging the use of cartograms in disease mapping. To this end, a series of tasks have been undertaken: a thorough review of cartographic visualization methodology and the history of disease mapping, an experimental attempt to modify cartogram construction techniques, an online survey to collect users’ views about cartograms and disease mapping, an observation of the practical strategies adopted for developing cartograms in the Worldmapper project, and extensive discussion and analysis of current trends in cartogram construction techniques and disease mapping. The study confirms that the nature of cartograms limits their application because the inevitable distortions produced by cartograms render them unfamiliar, even unrecognizable, to map readers and even cartographers. If the use of cartograms is to be promoted, they must be more readily understood. First, production techniques must be refined to produce cartograms that offer minimal levels of distortion; second, effective instructions must be supplied to teach users how to read them; and third, varied general education about new visual thinking must be carried out in order to encourage a wider use of cartograms in the future.